Abstract
OBJECTIVE: Social determinants of health (SDOH), including race, have a key role in total hip arthroplasty (THA) disparities. We compared the collective influence of community-level SDOH to the influence of individual factors such as race, on THA outcomes. METHODS: This retrospective cohort study of the Pennsylvania Health Care Cost Containment Council Database (2012-2018) included 105,336 patients undergoing unilateral primary elective THA. We extracted "community" factors from the US census by geocoding patient zip codes, including walkability index, household income, foreign-born individuals, English proficiency, computer and internet access, unpaid family workers, those lacking health insurances, and education. We trained an explainable boosting machine, a modern form of generalized additive models, to predict 90-day readmission, 90-day mortality, one-year revision, and length of stay (LOS). Mean absolute scores were aggregated to measure variable importance (ie, variables that contributed most to the prediction). RESULTS: The rates of readmission, revision, and mortality were 8%, 1.5%, and 0.3%, respectively, with a median LOS of two days. Predictive performance measured by area under the receiver operating characteristic curve was 0.76 for mortality, 0.66 for readmission, and 0.57 for one-year revision. For LOS, the root mean squared error was 0.41 (R(2) = 0.2). The top three predictors of mortality were community, discharge location, and age; for readmission, they were discharge location, age, and comorbidities; for revision, they were community, discharge location, and comorbidities; and for LOS, they were discharge location, community, and comorbidities. CONCLUSION: Community-level SDOH were significantly more important than individual race in contributing to the prediction of THA outcomes, especially for 90-day mortality.